Electric motor driven tool for orthopedic impacting

ABSTRACT

An orthopedic impacting tool comprises a motor, an energy storage chamber, a striker, and an anvil. The motor stores energy in the energy storage chamber and then releases it, causing the striker to apply a controlled force on an adapter to create a precise impact for use in a surgical setting. The tool may further comprise a combination anvil and adapter. The tool further allows forward or backward impacting for expanding the size or volume of the opening or for facilitating removal of a broach, implant, or other surgical implement from the opening. An energy adjustment control of the tool allows a surgeon to increase or decrease the impact energy. A light source and hand grips improve ease of operation of the tool.

CROSS-REFERENCE TO RELATED APPLICATIONS

It is noted that more than one application for reissue of U.S. Pat. No.8,602,124 has been filed. Each of copending U.S. patent application Ser.Nos. 14/850,588; 14/850,620; 14/850,639; 14/850,660; 14/850,674; and14/850,695 were filed on Sep. 10, 2015 for reissue of U.S. Pat. No.8,602,124.

The present application is a reissue of U.S. Pat. No. 8,602,124 issuedDec. 10, 2013 from U.S. patent application Ser. No. 13/790,870, filed onMar. 8, 2013, which is a continuation of and claims priority under 35U.S.C. §120 on the pending U.S. patent application Ser. No. 13/759,813,filed on Feb. 5, 2013, now abandoned, the disclosure of which isincorporated by reference, which '813 application is acontinuation-in-part of and claims priority under 35 U.S.C. § § 120 onthe pending U.S. patent application Ser. Nos. No. 12/980,329, filed onDec. 29, 2010, now U.S. Pat. No. 8,695,726, and is a continuation of andclaims priority under 35 U.S.C. § 120 on U.S. patent application Ser.No. 13/466,870, filed on May 8, 2012, now U.S. Pat. No. 8,393,409, aswell as under 35 USC U.S.C. § § 119 on U.S. Provisional PatentApplication 61/603,320, filed on Feb. 26, 2012, U.S. Provisional PatentApplication 61/682,915, filed on Aug. 14, 2012, and U.S. ProvisionalPatent Application 61/734,539, filed on Dec. 7, 2012, the disclosures ofwhich are incorporated by reference. The present '870 application isalso a continuation-in-part of and claims priority under 35 U.S.C. § §120 on the pending U.S. patent application Ser. Nos. 12/980,329, filedon Dec. 29, 2010, now U.S. Pat. No. 8,695,726, and 13/466,870, filed onMay 8, 2012, now U.S. Pat. No. 8,393,409, the disclosures of which areincorporated by reference. The '6,870 application is also a continuationof and claims priority under 35 U.S.C. § 120 on U.S. patent applicationSer. No. 13/337,075, filed on Dec. 24, 2011, now abandoned, and is acontinuation-in-part of and claims priority under 35 U.S.C. § 120 onU.S. patent application Ser. No. 12/980,329, filed on Dec. 29, 2010, nowU.S. Pat. No. 8,685,726. Additionally, the present application claimspriority under the benefit of 35 USC U.S.C. § § 119 for pending U.S.Provisional Patent Application Ser. Nos. 61/734,539, filed on Dec. 7,2012, and 61/682,915, filed on Aug. 14, 2012, the disclosures of whichare incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to electric tools for impacting inorthopedic applications, and, more particularly, to an electric motordriven tool for orthopedic impacting that is capable of providingcontrolled impacts to a broach or other end effector.

BACKGROUND

In the field of orthopedics, prosthetic devices, such as artificialjoints, are often implanted or seated in a patient's body by seating theprosthetic device in a cavity of a bone of the patient. Typically, thecavity must be created before the prosthesis is seated or implanted, andtraditionally, a physician removes and or compacts bone to form thiscavity. A prosthesis usually includes a stem or other protrusion thatserves as the particular portion of the prosthesis that is inserted intothe cavity.

To create such a cavity, a physician may use a broach, which broachconforms to the shape of the stem of the prosthesis. Solutions known inthe art include providing a handle with the broach, which handle thephysician may grasp while hammering the broach into the implant area.Unfortunately, this approach is clumsy and unpredictable as beingsubject to the skill of the particular physician. This approach almostwill always inevitably result in inaccuracies in the location andconfiguration of the cavity. Additionally, the surgeon suffers fromfatigue in this approach due to the constant hammering. Finally, thisapproach carries with it the risk that the physician will damage bonestructure in unintended areas.

Another technique for creating the prosthetic cavity is to drive thebroach pneumatically, that is, by compressed air. This approach isdisadvantageous in that it prevents portability of an impacting tool,for instance, because of the presence of a tethering air line, air beingexhausted from a tool into the sterile operating field and fatigue ofthe physician operating the tool. Further, this approach, as exemplifiedin U.S. Pat. No. 5,057,112, does not allow for precise control of theimpact force or frequency and instead functions very much like ajackhammer when actuated. Again, this lack of any measure of precisecontrol makes accurate broaching of the cavity more difficult.

A third technique relics on computer-controlled robotic arms forcreating the cavity. While this approach overcomes the fatiguing andaccuracy issues, it suffers from having a very high capital cost andadditionally removes the tactile feedback that a surgeon can get from amanual approach.

A fourth technique relies on the author's own prior disclosures to use alinear compressor to compress air on a single stroke basis and then,after a sufficient pressure is created, to release the air through avalve and onto a striker. This then forces the striker to travel down aguide tube and impact an anvil, which holds the broach and or othersurgical tool. This invention works quite well, but, in the process oftesting it, does not allow for a simple method to reverse the broachshould it become stuck in the soft tissue. Further, the pressure of theair results in large forces in the gear train and linear motionconverter components, which large forces lead to premature wear oncomponents.

Consequently, there exists a need for an impacting tool that overcomesthe various disadvantages of the prior art.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages of the prior art, an electricmotor-driven orthopedic impacting tool configured to include all theadvantages of the prior art and to overcome the drawbacks inherenttherein is provided. The tool may be used by orthopedic surgeons fororthopedic impacting in hips, knees, shoulders and the like. The tool iscapable of holding a broach, chisel, or other end effector and gentlytapping the broach, chisel or other end effector into the cavity withcontrolled percussive impacts, resulting in a better fit for theprosthesis or the implant. Further, the control afforded by such anelectrically manipulated broach, chisel, or other end effector allowsadjustment of the impact settings according to a particular bone type orother profile of a patient. The tool additionally enables proper seatingor removal of the prosthesis or the implant into or out of an implantcavity and advantageously augments the existing surgeon's skill inguiding the instrument.

In an embodiment, an electric motor-driven orthopedic impacting toolcomprises a power source (such as a battery), a motor, a control means,a housing, a method for converting the rotary motion of the motor to alinear motion (hereafter referred to as a linear motion converter), atleast one reducing gear, a striker, a detent and an energy storagemeans, which energy storage means can include either compressed air or avacuum. The tool may further include an LED, a handle portion with atleast one handgrip for the comfortable gripping of the tool, an adapterconfigured to accept a surgical tool, a battery and at least one sensor.At least some of the various components are preferably contained withinthe housing. The tool is capable of applying cyclic impact forces on abroach, chisel, or other end effector, or an implant and of finelytuning an impact force to a plurality of levels.

In a further embodiment, the handle may be repositionable or foldableback to the tool to present an inline tool wherein the surgeon pushes orpulls on the tool co-linearly with the direction of the broach. This hasthe advantage of limiting the amount of torque the surgeon may put onthe tool while it is in operation. In a further refinement of the handgrip, there may be an additional hand grip for guiding the surgicalinstrument and providing increased stability during the impactingoperation.

In a further embodiment, the broach, chisel or other end effector can berotated to a number of positions while still maintaining axialalignment. This facilitates the use of the broach for various anatomicalpresentations during surgery.

In a further embodiment, the energy storage means comprises a chamber,which is under at least a partial vacuum during a portion of an impactcycle.

In a further embodiment the linear motion converter uses one of a slidercrank, linkage mechanism, cam, screw, rack and pinion, friction drive orbelt and pulley.

In an embodiment, the linear motion converter and rotary motor may bereplaced by a linear motor, solenoid or voice coil motor.

In an embodiment, the tool further comprises a control means, whichcontrol means includes an energy adjustment element, and which energyadjustment element may control the impact force of the tool and reduceor avoid damage caused by uncontrolled impacts. The energy may beregulated electronically or mechanically. Furthermore, the energyadjustment element may be analog or have fixed settings. This controlmeans allows for the precise control of the broach machining operation.

In an embodiment, an anvil of the tool includes at least one of twopoints of impact and a guide that constrains the striker to move in asubstantially axial direction. In operation, the movement of the strikeralong the guide continues in the forward direction. A reversingmechanism can be used to change the point of impact of the striker andthe resulting force on the surgical tool. Use of such a reversingmechanism results in either a forward or a rearward force being exertedon the anvil and/or the broach or other surgical attachment. As used inthis context, “forward direction” connotes movement of the strikertoward a broach, chisel or patient, and “rearward direction” connotesmovement of the striker away from the broach, chisel or patient. Theselectivity of either bidirectional or unidirectional impacting providesflexibility to a surgeon in either cutting or compressing materialwithin the implant cavity in that the choice of material removal ormaterial compaction is often a critical decision in a surgicalprocedure. Furthermore, it was discovered in the use of the author'sprior disclosure that the tool would often get stuck during theprocedure and that the method of reversal in that tool was insufficientto dislodge the surgical implement. This new embodiment overcomes theselimitations. In an embodiment the impact points to communicate either aforward or rearward force are at least two separate and distinct points.

In an embodiment the anvil and the adapter comprise a single element, orone may be integral to the other.

In an embodiment the tool is further capable of regulating the frequencyof the striker's impacting movement. By regulating the frequency of thestriker, the tool may, for example, impart a greater total time-weightedpercussive impact, while maintaining the same impact magnitude. Thisallows for the surgeon to control the cutting speed of the broach orchisel. For example, the surgeon may choose cutting at a faster rate(higher frequency impacting) during the bulk of the broach or chiselmovement and then slow the cutting rate as the broach or chiselapproaches a desired depth. In typical impactors, as shown in U.S. Pat.No. 6,938,705, as used in demolition work, varying the speed varies theimpact force, making it impossible to maintain constant (defined as+/−20%) impact energy in variable speed operation.

In an embodiment the direction of impacting is controlled by the biasingforce placed by a user on the tool. For example, biasing the tool in theforward direction gives forward impacting and biasing the tool in therearward direction gives rear impacting.

In an embodiment the tool may have a lighting element to illuminate awork area and accurately position the broach, chisel, or other endeffector on a desired location on the prosthesis or the implant.

In an embodiment the tool may also include a feedback system that warnsthe user when a bending or off-line orientation beyond a certainmagnitude is detected at a broach, chisel, or other end effector orimplant interface.

In an embodiment the tool may also include a detent that retains thestriker and which may be activated by a mechanical or electrical meanssuch that the energy per impact from the tool to the surgical endeffector is increased. In an embodiment, the characteristics of thisdetent are such that within 30% of striker movement, the retention forceexerted by the detent on the striker is reduced by 50%.

These together with other aspects of the present disclosure, along withthe various features of novelty that characterize the presentdisclosure, are pointed out with particularity in the claims annexedhereto and form a part of the present disclosure. For a betterunderstanding of the present disclosure, its operating advantages, andthe specific objects attained by its uses, reference should be made tothe accompanying drawings and detailed description in which there areillustrated and described exemplary embodiments of the presentdisclosure.

DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will become betterunderstood with reference to the following detailed description andclaims taken in conjunction with the accompanying drawings, wherein likeelements are identified with like symbols, and in which:

FIG. 1 shows a perspective view of an orthopedic impacting tool inaccordance with an exemplary embodiment of the present disclosure inwhich a motor, linear motion converter, and vacuum as energy storagemeans are used;

FIG. 2 shows an exemplary position of the piston wherein the vacuum hasbeen created;

FIG. 3 shows the striker being released and the striker moving towardsimpacting the anvil in a forward direction;

FIG. 4 shows the striker being released and the striker moving such thatthe anvil will be impacted in a reverse direction;

FIG. 5 shows the vacuum piston moving back towards a first position andresetting the striker;

FIG. 6 shows an exemplary embodiment of a tool in which a compressionchamber is used to create an impacting force;

FIG. 7 shows an exemplary embodiment of a tool in which a valve is usedto adjust the energy of the impact of the striker;

FIG. 8 shows an exemplary embodiment of a tool in which the strikerimparts a surface imparting a rearward force on the anvil;

FIG. 9 shows an exemplary embodiment of a tool in which the strikerimparts a forward acting force on the anvil; and

FIG. 10 shows a comparison of the force vs. time curve between a sharpimpact and a modified impact using a compliance mechanism in accordancewith an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

The best mode for carrying out the present disclosure is presented interms of its preferred embodiments, herein depicted in the accompanyingfigures. The preferred embodiments described herein detail forillustrative purposes are subject to many variations. It is understoodthat various omissions and substitutions of equivalents are contemplatedas circumstances may suggest or render expedient, but are intended tocover the application or implementation without departing from thespirit or scope of the present disclosure.

The terms “a” and “an” herein do not denote a limitation of quantity,but rather denote the presence of at least one of the referenced items.

The present disclosure provides an electric motor-driven orthopedicimpacting tool with controlled percussive impacts. The tool includes thecapability to perform single and multiple impacts as well as impactingof variable and varying directions, forces and frequencies. In anembodiment the impact force is adjustable. In another embodiment adetent may be provided, which detent facilitates the generation of ahigher energy impact. In yet another embodiment the impact istransferred to a broach, chisel, or other end effector connected to thetool.

The tool may further include a housing. The housing may securely coverand hold at least one component of the tool. In an embodiment, thehousing contains a motor, at least one reducing gear, a linear motionconverter, a gas chamber, a striker, a force adjuster, a control means,an anvil, a forward impact surface and a different surface for rearwardimpact.

The tool further may include a handle portion with at least one handgrip for comfortable and secure holding of the tool while in use, and anadapter, a battery, a positional sensor, a directional sensor, and atorsional sensor. The tool may further comprise a lighting element suchas an LED to provide light in the work area in which a surgeon employsthe tool. The anvil may be coupled to a broach, chisel or other endeffector through the use of an adapter, which adapter may have a quickconnect mechanism to facilitate rapid change of different broachingsizes. The anvil may further include a locking rotational feature toallow the broach to be presented to and configured at differentanatomical configurations without changing the orientation of the toolin the surgeon's hands.

Referring now to FIGS. 1 through 5, in an embodiment, the linear motionconverter 12 comprises a slider crank mechanism, which slider crank isoperatively coupled to the motor 8 and reducing gears 7. The toolfurther comprises a vacuum chamber 23 that accepts a piston 24 which maybe actuated by the linear motion converter 12. It will be apparent thatthe piston 24 may be actuated in more than one direction. The vacuum iscreated in the vacuum chamber 23 by the movement of piston 24 away fromstriker 25. The vacuum created in the vacuum chamber 23 is defined as apressure of less than 9 psia for at least a portion of the operationalcycle.

In an embodiment, the motor 8 of the tool causes the linear motionconverter 12 to move, which pulls a vacuum on the face of the striker 25and creates at least a partial vacuum in the vacuum chamber 23, as isshown in FIG. 2. The piston 24 continues to move increasing the size ofthe vacuum chamber 23 until it hits a forward portion of the striker 25(i.e., a portion of the strike that is proximate to the end effector orpatient), which dislodges the striker 25 from its detent 10 and allowsit to rapidly accelerate towards the end of the tool that is proximateto the end effector or patient. In an embodiment, the detent may bemechanical, electrical, or a combination thereof, with the preferreddetent shown in the figures as a magnet. A characteristic of the detent10 is that once the detent 10 is released or overcome, the retentionforce of the detent 10 on the striker 25 reduces by at least 50% withinthe first 30% movement of the striker 25. The impact of the striker 25on the anvil 14 communicates a force to the adapter 1 and the broach,chisel or other orthopedic instrument.

In an embodiment, the direction of the force on the anvil is controlledby the user's (such as a surgeon) force on the tool and a stroke limiter13. It has been determined that prior art tools may occasionally getstuck in a cavity and the impact of the striker in the aforementionedparagraph may be insufficient to dislodge the tool. In this presentembodiment, when the tool is being pulled away from the cavity, thestriker 25 will not impact the anvil 14, but will impact an alternatesurface and thereby communicate a rearward force on the anvil 14. Thisimpact surface is shown in an exemplary embodiment as actuation pin 27.Actuation pin 27 communicates a force to lever arm 17, whichcommunicates a rearward force on the anvil 14, and specifically on theanvil retract impact surface 26. This embodiment has the unexpectedbenefit of easily dislodging tools and instruments that have becomestuck in a surgical cavity, while retaining all the benefits of theexisting tool in terms of precision-controlled impacting. Thus, afurther advantage of this tool was discovered as it can be seen that thesurgeon can control the direction of the impacting by a bias that he orshe may place on the tool and, in so doing, can reduce the likelihood ofthe broach, chisel or other end effector from getting stuck in a patientor surgical cavity.

In a further embodiment, an electromagnet may be incorporated as thedetent 10 and released at an appropriate point in the operation cycle toallow the striker 25 to impact the anvil 14. Once the striker 25 hasbeen released from the detent 10, the air pressure on the rearward sideof the striker 25, propels it forward to impact the anvil 14 or otherstrike surface. The resultant force may be communicated through an endof the anvil 14 that is proximate to the anvil forward impact surface 16and, optionally, through the adapter 1 to which a broach, chisel, orother end effector for seating or removing an implant or prosthesis maybe attached.

The striker guide 11 may also have striker guide vent holes 20, whichallow the air in front of the striker 25 to escape, thus increasing theimpact force of the striker 25 on the anvil 14. The striker guide ventholes 20 may vent within the cavity of the tool body, thus creating aself-contained air cycle preventing air from escaping from the tool andallowing for better sealing of the tool. The position and the size ofthe striker guide vent holes 20 can also be used to regulate the impactforce. Further, it was unexpectedly found that adding the striker guidevent holes 20 increases the impact force of the striker 25 on the anvil14.

In an embodiment, as the piston 24 continues through its stroke it movestowards the rear direction, which movement brings it in contact withrear striker face 28 of striker 25 and moves it towards the rear of thetool. This allows the detent 10 to lock or retain the striker 25 inposition for the next impact. The piston 24 completes its rearwardstroke and preferably activates a sensor 22 that signals the motor 8 tostop such that the piston 24 rests at or near bottom dead center of thevacuum chamber 23. The vacuum chamber 23 preferably has a relief orcheck valve 9 or other small opening, which, in an embodiment, is partof the piston 24. The valve 9 may also be located at other points in thevacuum chamber 23 and allows for any air which may have accumulated inthe vacuum chamber 23 to be purged out of the vacuum chamber 23 duringeach cycle. In a further embodiment this valve effect could beaccomplished with a cup seal instead of an o-ring seal. This ensuresthat approximately atmospheric pressure is present in the vacuum chamber23 at a starting point in the operational cycle, thus ensuring that eachimpact utilizes the same amount of energy, as is important in orthopedicimpacting for at least the reason that it assures of a substantiallyconsistent force and impact rate in multi-impact situations. Thus, inone complete cycle, a forward or a rearward impacting force may beapplied on the broach, chisel, or other end effector, or on the implantor prosthesis.

In a further embodiment, the motor 8 of the tool causes the linearmotion converter 12 to move the piston 24 until the piston 24 moves asufficient distance such that the forward portion of the piston impactsa portion of the striker and overcomes the detent 10 that retains thestriker in the rear position. Once the striker has been released fromthe detent 10, the vacuum in the vacuum chamber 23 exerts a force on thestriker, which accelerates the striker, causing the striker to slideaxially down a cavity internal to the tool housing and strike the anvilforward impact surface 16. In FIG. 3, the anvil forward impact surface16 causes a forward movement of the anvil 14 and/or tool holder, and, inFIG. 4, the anvil retract impact surface 26 causes a rearward movementof the anvil 14 and/or tool holder. The resultant force is communicatedthrough an end of the anvil 14 that is proximate to the anvil forwardimpact surface 16 and, optionally, through the adapter 1 to which abroach, chisel, or other end effector for seating or removing an implantor prosthesis may be attached.

In another embodiment, the impact force may be generated using acompressed air chamber 5 in conjunction with a piston 6 and striker 4,as shown in FIGS. 6 through 9. In this embodiment, the motor 8 of thetool causes the linear motion converter 12 to move the piston 6 untilsufficient pressure is built within the compressed air chamber 5 that isdisposed between the distal end of the piston 6 and the proximate end ofthe striker 4 to overcome a detent 10 that otherwise retains the striker4 in a rearward position and or the inertia and frictional force thatholds the striker 4 in that rearward position. Once this sufficientpressure is reached, an air passageway 19 is opened and the air pressureaccelerates the striker 4, which striker 4 slides axially down a cavityand strikes the anvil 14. The air passageway 19 has a cross sectionalarea of preferably less than 50% of the cross sectional area of thestriker 4 so as to reduce the amount of retaining force required fromdetent 10. The resultant force is communicated through the end of theanvil 14 that is proximate to the anvil forward impact surface 16 and,optionally, through the adapter 1 to which a broach, chisel, or otherdevice for seating or removing an implant or prosthesis may be attached.

As the piston 6 continues through its stroke, it moves towards the reardirection, pulling a slight vacuum in compressed air chamber 5. Thisvacuum may be communicated through an air passageway 19 to the back sideof the striker 4, creating a returning force on the striker 4, whichreturning force causes the striker 4 to move in a rear direction, i.e.,a direction away from the point of impact of the striker 4 on the anvilforward impact surface 16. In the event that an adapter 1 is attached tothe anvil 14, a force may be communicated through the adapter 1 to whichthe broach, chisel, or other end effector for seating or removing animplant or prosthesis is attached.

Further, when the tool is being pulled away from the cavity, the striker4 will not impact the anvil 14, but may instead impact an alternatesurface and thereby communicate a rearward force on the anvil 14. Thisimpact surface is shown in an exemplary embodiment as actuation pin 27.Actuation pin 27 communicates a force to lever arm 17, whichcommunicates a rearward force on the anvil 14, and specifically on theanvil retract impact surface 26.

The tool may further facilitate controlled continuous impacting, whichimpacting is dependent on a position of a start switch (which startswitch may be operatively coupled to the power source or motor, forexample.) For such continuous impacting, after the start switch isactivated, and depending on the position of the start switch, the toolmay go through complete cycles at a rate proportional to the position ofthe start switch, for example. Thus, with either single impact orcontinuous impacting operational modes, the creation or shaping of thesurgical area is easily controlled by the surgeon.

A sensor 22 coupled operatively to the control means 21 may be providedto assist in regulating a preferred cyclic operation of the linearmotion converter 12. For example, the sensor 22 may communicate at leastone position to the control means 21, allowing the linear motionconverter 12 to stop at or near a position in which at least 75% of afull power stroke is available for the next cycle. This position isreferred to as a rest position. This has been found to be advantageousover existing tools in that it allows the user to ensure that the toolimpacts with the same amount of energy per cycle. Without this level ofcontrol, the repeatability of single cycle impacting is limited,reducing the confidence the surgeon has in the tool.

The tool is further capable of tuning the amount of impact energy percycle by way of, for example, an energy control element 18. Bycontrolling the impact energy the tool can avoid damage caused byuncontrolled impacts or impacts of excessive energy. For example, asurgeon may reduce the impact setting in the case of an elderly patentwith osteoporosis, or may increase the impact setting for more resilientor intact athletic bone structures.

In an embodiment, the energy control element 18 preferably comprises aselectable release setting on the detent 10 that holds the striker 25.It will be apparent that the striker 25 will impact the anvil 14 withgreater energy in the case where the pressure needed to dislodge thestriker 25 from the detent 10 is increased. In another embodiment, thedetent 10 may comprise an electrically controlled element. Theelectrically controlled element can be released at different points inthe cycle, thus limiting the size of the vacuum chamber 23, which isacting on the striker 25. In an embodiment, the electrically controlledelement is an electromagnet.

In another embodiment, the vacuum chamber 23 or compressed air chamber 5may include an energy control element 18, which takes the form of anadjustable leak, such as an adjustable valve. The leakage reduces theamount of energy accelerating the striker 4 or 25, thus reducing theimpact energy on the anvil 14. In the case of the adjustable leak,adjusting the leak to maximum may give the lowest impact energy from thestriker 4 or 25, and adjusting to shut the leak off (zero leak) may givethe highest impact energy from the striker 4 or 25.

The tool may further comprise a compliance means inserted between thestriker 4 or 25 and the surgical end effector, which purpose is tospread the impact force out over a longer time period, thus achievingthe same total energy per impact, but at a reduced force. This can beseen clearly as a result of two load cell tests on the instrument asshown in FIG. 10. This type of compliance means can limit the peak forceduring impact to preclude such peaks from causing fractures in thepatient's bone. In a further embodiment, this compliance means may beadjustable and in a still further embodiment the compliance means may beinserted between striker 4 or 25 and the anvil 14 or surgical tool. Inthis manner and otherwise, the tool facilitates consistent axialbroaching and implant seating. Preferably, the compliance meansincreases the time of impact from the striker to at least 4 millisecondsand preferable 10 milliseconds. This contrasts to impacting in which avery high force is generated due to the comparatively high strengths ofthe striker 4 or 25 and the anvil 14 (both steel, for example).Preferably, the compliance means comprises a resilient material such asurethane, rubber or other elastic material that recovers well fromimpact and imparts minimal damping on the total energy.

In a further embodiment, the adapter 1 may comprise a linkagearrangement or other adjustment means such that the position of thebroach, chisel or other end effector can be modified without requiringthe surgeon to rotate the tool. In an embodiment, the adapter 1 mayreceive a broach for anterior or posterior joint replacement througheither an offset mechanism or by a rotational or pivotal couplingbetween the tool and the patient. The adapter 1 may thereby maintain thebroach or surgical end effector in an orientation that is parallel orco-linear to the body of the tool and the striker 25. The adapter 1 mayalso comprise clamps, a vice, or any other fastener that may securelyhold the broach, chisel, or other end effector during operation of thetool.

In use, a surgeon firmly holds the tool by the handle grip or grips andutilizes light emitted by the LED to illuminate a work area andaccurately position a broach, chisel or other end effector that has beenattached to the tool on a desired location on the prosthesis or implant.The reciprocating movement imparted by the tool upon the broach, chiselor other end effector allows for shaping a cavity and for seating orremoval of a prosthesis.

The tool disclosed herein provides various advantages over the priorart. It facilitates controlled impacting at a surgical site, whichminimizes unnecessary damage to a patient's body and which allowsprecise shaping of an implant or prosthesis seat. The tool also allowsthe surgeon to modulate the direction, force and frequency of impacts,which improves the surgeon's ability to manipulate the tool. The forceand compliance control adjustments of the impact settings allow asurgeon to set the force of impact according to a particular bone typeor other profile of a patient. The improved efficiency and reducedlinear motion converter loads allow use of smaller batteries and lowercost components. The tool thereby enables proper seating or removal ofthe prosthesis or implant into or out of an implant cavity.

The foregoing descriptions of specific embodiments of the presentdisclosure have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit thepresent disclosure to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The exemplary embodiment was chosen and described in order tobest explain the principles of the present disclosure and its practicalapplication, to thereby enable others skilled in the art to best utilizethe disclosure and various embodiments with various modifications as aresuited to the particular use contemplated.

What is claimed is:
 1. An orthopedic impacting tool for striking anobject, the tool comprising: a motor; a linear motion converter; anenergy storage means; a detent; a control means; an adapter, saidadapter capable of holding a broach, chisel or other surgical implement;and a striker, said striker capable of impacting at least two distinctimpact surfaces, wherein a first impact surface moves said adapterforward and a second impact surface moves said adapter rearward, whereinsaid control means directs said motor to store an energy in said energystorage means and said energy storage means thereafter releases theenergy onto said striker causing said striker to move from a firstposition to a second position such that said striker is capable ofimparting a force upon said adapter in a direction that is dependent atleast in part on which surface said striker impacts.
 2. The tool asclaimed in claim 1, wherein said impact surface being impacted iscontrolled by a bias that a user puts on the tool.
 3. The tool asclaimed in claim 1, wherein said energy storage means includes a chamberoperating at less than 9 psia or a pressure in excess of 50 psia at ornear the point of peak energy storage.
 4. The tool as claimed in claim1, wherein said detent retains said striker in said first position untilsaid detent is released or overcome thus allowing said energy storagemeans to release the energy onto said striker.
 5. The tool as claimed inclaim 1, wherein said energy storage means further comprises a valve. 6.The tool as claimed in claim 1, wherein the tool further comprises anenergy control element, said energy control element used to adjust theimpact energy said striker exerts on said adapter.
 7. The tool asclaimed in claim 1, wherein the tool further comprises a stroke limiter,said stroke limiter limiting a stroke of said adapter to less than fiftypercent of a stroke of said striker.
 8. A surgical impactor for strikingan object with a repeatable, controlled striking force to impel asurgical implement in one of at least two opposing directions, theimpactor comprising: a drive mechanism configured to produce thestriking force; an energy controller configured to control storage andrelease of energy output from the drive mechanism to an energy storagemechanism to produce the repeatable, controlled striking force; anadapter configured to receive the surgical implement to interface theobject; a striker operable to impact a first surface of an actuator anda different second surface of an anvil responsive to the repeatable,controllable striking force delivered thereto, the impact of the strikeron the first surface of the actuator impelling the adapter in a firstdirection and the impact of the striker on the second surface of theanvil impelling the adapter in a direction opposite the first direction;and a detent mechanism configured to retain the striker in position. 9.The impactor of claim 8, wherein a selection of a direction of impact onthe first and second surfaces is based upon a user bias force applied tothe impactor.
 10. The impactor of claim 9, wherein the user bias forcein a direction of the object causes the striker to impact the firstsurface.
 11. The impactor of claim 9, wherein the user bias force in adirection away from the object causes the striker to impact the secondsurface.
 12. The impactor of claim 8, wherein the energy storagemechanism includes a chamber operating between 0 and 9 psia for aportion of a storage cycle.
 13. The impactor of claim 8, wherein theenergy storage mechanism includes a chamber that is under at least apartial vacuum when the striker impacts the first surface to impel thesurgical implement in the first direction.
 14. The impactor of claim 8,wherein the energy storage mechanism is a compressed air chamber. 15.The impactor of claim 8, further comprising: an energy adjustmentmechanism to adjust the striking force the striker delivers to theadapter in accordance with a patient profile.
 16. The impactor of claim8, further comprising: a linear motion conversion mechanism to convertthe output of the drive mechanism to a linear motion.
 17. The impactorof claim 8, wherein upon release of the detent mechanism, a retentionforce of the detent mechanism on the striker is reduced by at leastfifty percent within a first thirty percent of a stroke of the striker.18. The impactor of claim 8, wherein the striker is operably linked tothe adapter by the impact of the striker on the first and secondsurfaces of the anvil.
 19. The impactor of claim 8, wherein the adapteris configured to releasably connect to the surgical implement.
 20. Theimpactor of claim 8, wherein the striker moves in a substantially axialdirection along a guide portion having openings therein for venting ofair during operation.
 21. The impactor of claim 16, further comprising:a sensor operably linked to the energy controller to regulate the linearmotion conversion mechanism to a preferred cyclic operation.
 22. Theimpactor of claim 21, wherein the sensor detects a position of thelinear motion conversion mechanism to limit a stroke to a percentageless than full power.
 23. A surgical impactor for striking an objectwith a repeatable, controlled striking force to impel a surgicalimplement in one of at least two opposing directions, the impactorcomprising: a drive mechanism configured to drive the impactor, anenergy controller configured to control storage and release of energyoutput from the drive mechanism to an energy storage device to producethe repeatable, controlled striking force; an adapter having a mountconfigured to receive the surgical implement; a striker operable toimpact a first surface of an actuator and a different second surface ofan anvil responsive to the repeatable, controllable striking forcedelivered thereto, the impact of the striker on the first surface of theactuator impelling the adapter in a first direction and the impact ofthe striker on the second surface of the anvil impelling the adapter ina direction opposite the first direction; and a detent mechanismconfigured to retain the striker in position.
 24. The impactor of claim8, wherein the actuator is a pin, and the impact of the striker on thefirst surface of the pin causes a rearward force to be communicated tothe anvil.
 25. The impactor of claim 8, wherein a distal surface of thestriker is operable to impact the first surface of the actuator and thesecond surface of the anvil responsive to the repeatable, controllablestriking force delivered thereto.